HOW ITS DONE

The mussels grown on the site in Torbay are of exceptional quality due to the low stocking densityand the abundant food source found in this open sea environment.

The mussels are a naturally occurring hybrid of the Mytilus Edulis mussel (the native or blue mussel) and Mytilus Galloprovincialis ( the Mediterranean mussel)

This hybrid appears to be well suited to both the environment conditions found in Torbay and also the higher water temperatures that occur in Torbay.

The mussels are harvested from the growing lines (collectors )when they are 50 to 60 mm long a size that is achieved when the mussels are 18 months to 2 years old and after grading at sea the mussels are landed and placed in the depuration tanks .

Mussels from the site in Torbay have proved to be popular with restaurants because of the high meat content which can get up to 45 % in the Autumn, gradually reducing to 35% at Christmas,and still maintain 30% yield in February.

Thinning and Transplanting

As summer progresses, the mussel seed grows rapidly on the lines and by August they are about 2 centimeters in length. The density at which they settled on the line is so great that the mussels will need to be thinned out so to allow for quicker and more uniform growth.

Starting in late summer the thinning process begins. Each one of the hundreds of seed collector lines is pulled up and stripped bare on to the deck of our mussel harvester John B.

The "seed" mussels are then fed into a "socking" machine which produces a continuous cotton stocking or socking filled with mussel seed with a rope through the middle of the stocking with plastic pegs to prevent slippage already fitted in the rope, at a density of about 150 mussels per foot of line. Each seed line will yield between 2 to 3 mussel harvest lines, each of the lines of mussels are 5 meters long.

Once filled, each of the socks are hung from a mussel line where they will stay and grow until they reach harvest size. The seed mussels in the sock put out byssal threads attaching themselves to the sock and one another; and the eventually grow through the mesh of the sock and appear to be a solid column of mussels once fully grown.

Natural Seeding of Mussels

We attempt to take advantage of the natural spawning cycle of the mussels in Torbay which culminates about the month of March of each year as the water temperatures begin to climb, and the big tides occur, usually at the spring equinox. In the early spring we suspend hundreds of fibrous lines from the semi submerged mussel lines anchored in Torbay. Each of our 120-meter long mussel lines will have 300 plus rope ladders fabricated in our workshops from fibrous rope which hang down in 5 meter continuous loops to maximize the collecting area When the conditions are right, the male and female mussels spawn releasing their eggs and sperm into the water where the eggs are immediately fertilized. The fertilized eggs become swimming larvae within a 24 hour period and remain so for a 3 week time span, at which time they go through another change where they develop their shell and other organs.

At this point they are ready to settle on something in the intertidal area; hopefully on the seed collector which we have placed on our long lines. As the mussel seed goes through its change from a swimming larvae to its shelled form, it develops a foot similar to a clam. However, on the base of the foot there is a gland which secretes a very strong cement to whatever it attaches itself to. When the small mussel (1/3 of a millimeter), is ready to settle on a solid substrate, it puts out its foot and applies a dab of cement to the seed collector lines which we have hanging from the mussel lines in the top 5 meters of water. After about three weeks of growing on the mussel collector lines, the small mussels become visible, this is normally in the first week of June. In a normal year, one can see literally thousands of these tiny mussels on each meter of a collector line. Once grown out to a more manageable size, this mussel seed will be stripped from this line and loaded into mussel socks at the proper density of about 200 per foot/600 per meter. Once attached to the line, the mussel pulls its foot back creating a thread of the cement which hardens on contact with the sea water, somewhat similar to the manner in which a spider makes its web.

The mussel will continue to put out these "byssal threads" until it is securely attached to the line. At that point it has pretty much found its home for life, although it can use its foot to attach to something nearby and still move a little bit. Once settled the mussels begin to feed.

 
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Email: info@brixhamseafarmsltd.co.uk Tel: 01803 843080